This study exposes, for the first time, the effect of Electrochemical Promotion (EPOC) by potassium cations on Pt catalyst for low temperature CO oxidation process. The effect of catalyst polarization drastically increased the catalytic rate for more than 11 times by decreasing the light-off temperature by almost 40 °C. The promotional phenomenon was found to be reversible due to the formation and decomposition of potassium compounds on Pt surface that enhanced the adsorption of O2 at the expense of CO. The achieved results demonstrated that Electrochemical Promotion of Catalysis could be applied to improve the performance of catalytic converters at lower temperatures.